Safety mechanism for furnaces



Dec. 11 1923 1,477,027

G. N. BLANCHARD SAFETY MECHANISM FOR FURNACES Filed D90. 13 1922 55 ,1 1 5,92

ti t lit ELANCHARD, 033 51th FRANGISCU, EALIEFORNEA, .U" BURNER GUME'ANY, 0E SAN FRANCESUQ, CALIFORNIA, 1 3. (ct

rooms QAFETSZ' MECHAHIEth FOR Application filed December 13, 2.92%. serial Ho. 8063MB.

To aZZ whom it may 6011087911 Be it known that L Gno'nor. N. BLANGIIARI),

a citizen of the United States, residing at the city-and county of San Francisco, and State of California, have invented certain new and useful Improvements in Safety lllechanism for Furnaces, of which the following is a. specification.

it has been. found advisable, if not necessorry, to provide in heating apparatuses, particularly hot air furnaces, a type of control adapted to reduce the intensity of the heat in the firebox at all the hot air outlets are closed. thus preventing the overheating of a furnace to such a point as to fire the building.

My present invention relates to an automatic control designed particularly for incorporation within a hot air furnace to he acted on by the temperature of the air in one of the hot air Outlets whereby the in tensity of the heat in the firebox is reduced on the temperature of the air exceeding a. predetermined degree.

Among the objects of this invention is to provide a. construction which is operated by the melting of anelement acted on by the temperature of the heated air and known to fuse on the temperature exceeding a certain degree; one wherein the element may be readily renewed after it has once fused containing an indicator denoting when the element has fused; and one wherein the finsing of'the element permits the operation of n Weighted member to actuate a movable member for varying the intensity of the heat in the firebox on the air temperature 1 beyond a predetermined degree.

With tie above mentioned and other objects in view, the invention consists in the novel construction and combination of parts hereinafter described, illustrated in the accompsnyinq/ drawings, and set forth in the cleims heneto appended, it being understood that various changes in the form. propoi tion, siz and minor details of construction within is. e scope of the cla-ims'may be resorted to without d parting from the spirit or safcrifieino,- any the advantages of tho invention,

such times asone.

"fulcrum l" the invention,

To more fully comprehend accon'i punying reference is directedto the drawings. wherein 1- Fig. 1 is a view in. front elevation of the preferred embodiment of my invention so 55 plied to a hot air furnace with the center of the lever broken away illustrating the instructions contained on the plate and exposed when the lever'drops.

Fig. particularly a "fusible member in the tubular support.

Referring more particularly to the several views of the drawings wherein like charcoters of reference designate corresponding to pal-ts 1 indicates the wall of a firebox 2 which is adapted to heat the air passing up wardly in the direction of the arrows 3 in the flue or duct 4 adjacent to said firebox. In this present disclosure, the firebox is 70 adapted to be heated by ahvdrocarbon fuel burner 5, the fuel feed to which is supplied through valve controlled pipe 5 by a pump operated by an electric motor 5 the operation of which is in turn controlled to by a switch (5 preferably positioned on the front Wall 7 of the furnace. It is to be understood that this switch element '6 is broadly illustrative of a, control to: the heating; element, us ii desired the same may to he in the of a valve for controlling the fuel supply, or a damper for controlling the air for combustion admitted imo the firebox or an additional supply of air into the duct The switch 6 curries a inovuhie member 8 and with the some is adapted to coact the bifurcated operating member 9 carried by a member 10 extending through a slot or opening 11 in the furnace front wall 7. The member 10 is secured to a. weighted Q operating rod 12 vertically movable in a guide 13 :it its iowc" end, and. to the upper end of said rod 1% is pivotally connected as at 14 the free end of u lever 15. is carried on the inner end I grossing through the i v to the s nd of" said member cured an lever 17 i free end finger ip 18. that the entire 5 2 15 a. sectional View illustrating 6o 17 and 18 is adapted for downward gravity movement to actuate the member 8, and thereby reduce the intensity of the heat in the firebox 2. The bearing fulcrum 16 is carried by a plate 19 detachably secured over an opening 20 in the furnace front ,Wall 7, and inwardly from said plate extends an'open ended tubular guide 21 provided with a stop 22 at its inner end in close proximity to the rod 12, said guide terminating at a point immediatel below the lever 15 when the same is in its fully elevated position, as indicated in Fig. 2.

'Removabl inserted into the guide 21 is an element, as or example a metal 23, adapted for fusing or melting at a known tempera ture, said element 23 when fully inserted into said guide is adapted to lie beneath the lever 15 and retain the rod 12 in its elevated position. The exposed end of the element 23 adapted for fusing on the tempera ture of the air within the duct 4 increasing above the melting point of the element, is adapted to release the lever 15, permitting the weight of the lever and its associated parts to drop by gravity and actuate the member 8 to cause a reduction in the heat intensity of the firebox. On .the dropping of the lever, the member 17 is adapted in its movement to expose an indication on the plate 19, to the effect that the fuse or element 23 needs replacement. After the actuation of the member 8 on the fusing of the element 23, the operator grasps the handle 18 to raise the lever 15 above the inner end of the guide 21, inserts a new element or fuse Within the guide so that the same will support the lever 15 and then raises the movable member 8 after which time the apparatus is again adapted for station. If desired, the movement of the rec end of the lever may be controlled by the fixed upper and lower stops 2 1 and 25. Having thus described my invention, what I claim as new and desire to protect by Letters Patent of the United Stairs is ,1. In combination with a hot air duct, an electric switch, mechanism for operating Said switch, a horizontally disposed support projecting into the said duct through its wall, and a fusible member removably positioned within and projecting into said duct beyond the inner end of said support for supporting and retaining said mechanism in inoperative position, said member adapted to fuse on the temperature in said duct attaining a predetermined degree for releasing said mechanism.

2. In combination with a hot air furnace provided with a firebox and an air circulating duct heated thereby, a movable means adapted when operated for controlling the fire in said firebox, a. movable rod for oper ating said movable means, an adjustable connection between said rod and movable means, an open ended tubular guide extcnding horizontally into the duct, the outer end of said guide lying exteriorly of the duct, a fusible member insertable into said uide through its outer end, the inner end 0' said fusible member adapted to project beyond theiend of said tubular guide to retain said rod in an elevated ino erative osition, and adapted to fuse to release suit rod on the temperature of the air within said duct exceeding a predetermined d rec, and means exteriorly of the furnace an associated with .the rod to permit the manual raising of said rod.

' In testimony whereof I have signed my name to this specification.

GEORGE N. BLANCHARD. 

